Hi slowsider,
Taping an AC joint is pretty simple- your sporty friend could probably do it for you. Taping will help to give you pain relief by providing external support to the joint as it heals. It will give you more support than a simple sling. There are more complicated slings and braces that you can buy (order through a physio or health professional) which make it easier in these type of situations as it is easier to use a brace repetitively than to tape repetitively (can get expensive and also irritate your skin). Bracing or taping is definitely a good idea as it will hold the joint in an optimal position as the scarring of the ligaments attaching the joint occurs. It will also help to carry some of the weight of the arm and stop you from getting complications such as a sore neck from altered use of your arm.
However, it is a definitely a good idea to also see a physio for further assessment and treatment (such as ultrasound), advice and exercises- have you been to one yet?